[BREAKING] Refactor NimBLEServer

* General code cleanup
* `NimBLEServerCallbacks::onMTUChanged` renamed to `NimBLEServerCallbacks::onMTUChange` to be consistent with the client callback.
* `NimBLEServer::getPeerIDInfo` renamed to `NimBLEServer::getPeerInfoByHandle` to better describe it's use.
* Use a std::array to store client connection handles instead of std::vector to reduce memory allocation.
* `NimBLEServer::disconnect` now returns `bool`, true = success,  instead of `int` to be consistent with the rest of the library.

Author: h2zero

src/NimBLEAdvertising.cpp

@@ -199,12 +199,7 @@ bool NimBLEAdvertising::start(uint32_t duration, const NimBLEAddress* dirAddr) {
 # if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)
     NimBLEServer* pServer = NimBLEDevice::getServer();
     if (pServer != nullptr) {
-        if (!pServer->m_gattsStarted) {
-            pServer->start();
-        } else if (pServer->getConnectedCount() >= NIMBLE_MAX_CONNECTIONS) {
-            NIMBLE_LOGE(LOG_TAG, "Unable to advertise; Max connections reached");
-            return false;
-        }
+        pServer->start(); // make sure the GATT server is ready before advertising
     }
 # endif
 

src/NimBLEExtAdvertising.cpp

@@ -62,9 +62,7 @@ bool NimBLEExtAdvertising::setInstanceData(uint8_t instId, NimBLEExtAdvertisemen
 # if defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)
     NimBLEServer* pServer = NimBLEDevice::getServer();
     if (pServer != nullptr) {
-        if (!pServer->m_gattsStarted) {
-            pServer->start();
-        }
+        pServer->start(); // make sure the GATT server is ready before advertising
     }
 
     int rc = ble_gap_ext_adv_configure(